Polyphase Deformation of Ajabgarh Stage Rocks, Delhi Group, Around Narnaul, Mohindergarh District, Haryana, India

A detailed study and analysis of all the planar and linear elements in the lithic units of the area, in both meso and macro scale reveal that they bear the impress of three phases of folding, F₁ F₂ and F₃. The most dominant phase is the second phase resulting in open asymmetric folding with high wave length/amplitude which express in mesoscale crenulations on the planar surface of F₁ folding. The F₁ phase is responsible for the regional foliation S₁ which is parallel to lithic banding S₀. The tight isoclinal folds develop appressed surface which act as form-surface of F₂. The F₁ and F₂ are generally co-axial. The last phase of folding F₃appear as broad open cross-folds broadly warping the pre-existing foliation. This phase can distinctly be observed on map scale.

Distinction between each phase and the associated structures is based on the overprinting relations, in particular the bending of axial surface foliation and other interference patterns between the existing phases. Structural analysis of the area indicates operation of a predominantly sub-horizontal NW-SE oriented stress.